Turbo end bell.



Patented July 16, 1918.

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R. E. GILMAN.

- TURBO END BELL.

APPLICATION man MAR. 4. I915.

Patented July 16, 1918.

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. UNITED STATES PATENT oFFioE.

RALPH E. GILIVIAN, OF PITTSBURGH, PENNSYLF'ANIA, ASSIGlN'OR TOWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

TURBO END BELL.

It all whom it may concern:

Be it known that I, RALPH E. GILMAN, a citizen of the United States, anda resident of Pittsburgh, in the county of Allegheny and State ofPemisylvania, have invented a new and useful Improvement in Turbo EndBells, of which the following isa specification.

My invention relates to inclosing end members or end bells fordynamo-electric machines, and it has for its object to provide an endbell in which the heating caused by ma netic conditions within thedynamo electric machine is reduced to a minimum.

A further object of my invention is to provide a device that is simpleand ineX- pensive to construct and which may be readily embodied inexisting types of end bells and thereby improve the efficiency andoperating characteristics of the associated dynamo-electric machines.

In the design and construction ofdynamoelectric machines and especiallyof turbo generators of large capacity it has been found desirable toprovide end bells that completely inclose the end port ions'of,themachine, owing tothe necessity of having the "entilating system underpressure. I The iron or steel end bells that'have heretofore beenemployed have been subject'to excessive heating caused by fringingmagnetic lines of force from both the field magnet and armature membersof the machine that enter the end bells in a direction substantiallynormal to the faces thereof- The eddy currents produced by the abovefringing magnetic field are particularly noticeable in turbo generatorsof a well-known type of construction in which the end portions of thearmature coils extend beyond the core and into theend bells.

'The above-mentioned objections may be overcome by the obvious expedientofmoving the end bells far enough away from the field magnet andarmature members to limit the number of magnetic lines of force enteringthem to a reasonable value. The use of such expedient is, however, open"to serious objections for the reason that it necessitates a furtherseparation of the shaft bearings, and it is well known that, in thedesign of high-speed turbo generators, the distance between bearingsshould be reduced to the smallest possible limit.

By my invention, I propose to eliminate Specification of Letters Patent.

mentioned an outwardly what larger than that of the Patented July 16,1918.

Application filed March 4, 1915. Serial m5. 12,132.

the heating due to the circulation of eddy currents in the end bells,and to provide end bells that may be mounted as closely to the fieldmagnetand armature members as may be desirable, thereby allowing theshaft bearings to be brought as closely together as clearances willpermit. In the construction bf an end bell in accordance with myinvention, that portion of the end bell adjacent to the field magnet andarmature members is formed of non-magnetizable and insulating materialsfor the purpose of eliminating the objectionable eddy current losses.The complete end bell is preferably formed of two half sections tofacilitate its assembly.

In the accompanyingdrawings, Figure 1 is aview, in front elevation, ofa'portion of an end bell constructed in accordance with my invention;Fig. 2 is a View, in side elevation, of an end bell mounted on thestator of a dynamo-electric machine; Fig. 3is asectional View along theline CD of Fig. 1; Fig. i is a sectional View. along the line AB of Fig.1; Fig. 5 is a sectional View along the line EF of Fig. 1, and Figs. 6,7 and 8 are detail views of parts of the structure shown in Fig. 1. "Adynamoelectrie machine comprises a stationary armature member 1 providedwith apluralityof windings 2, and a field magnet member-3 rotatablymounted on a shaft 4. A half-section 5 of an end-bell member, preferablyformed of cast iron or any other suitable material,is provided withprojecting flange 6 that is adapted to be secured to the stator frame 1by means of a plurality of bolts 7 and is disposed betWeen thefield-magnet member 3 and the pedestal bearing 8 forthe shaft 4. Themember 5 is so formed as to inclose onehalf of the end portion of themachine and is provided with a plurality of lugs 9 whereby two similarhalf-sections may be drawn toward each other and secured together toform a complete end bell by means of through-bolts l0. A se mi-circularopening 11- is provided in the member 5, and that portion thereofsurrounding the opening is provided with a concentric annular groove 12.An annular ring 13, preferably formed of brass or other suitablenon-magnetizable material and with an inside diameter someshaft 4, issup ported concentrically, with respect to the Shaft, by meanest aplurality of equally spaced and radially extending arms 1 k that aresecured, at their outer ends, in the groove 12 of the member 5 by meansof bolts 15. The arms 14 are formed of brass orother suitablenon-magnetizable material and are formed with parallel end portionsconnected by an'inclined middle portion so that the ring 13 is heldinwardly toward the rotatable field-magnet member 3, thereby allowing.'the shaft bearing 8 to be located closely adin order to prevent theexistence of a closed jacent to the machine. The arms 14 are secured, attheir ends, in an annular groove 16 formed in the ring 13, by means ofbolts 17. The skeleton frame, thus formed by the arms'14 and ring 13,serves to support a plurality 'of sections 18 formed preferably ofmicarta or other hard and durable insulating material and provided,along their edges, with notches 19-, as best shown in Fig. 6. Theinclined portions of the arms 14 and a plurality of strips 20 ofinsulating material are provided with corresponding holes 21 so thatadjacent sections 18 may be secured be tween the arms 14 and strips 20by means of bolts 'A plurality of insulating washers 23 are insertedbetween the ring 13 and the arms 14, or at any other suitable point,

electric circuit between the ring 13 and the end bell member.

From the foregoing description, it is apparent that that portion of thecomplete end bell adjacent to the extending portions of the armaturewindings 2 and the field magnet member 3 is formed entirely ofinsulating and non-magnetizable material in order to avoid excessiveheating of the end bell produced by the cutting of the, magnetic linesof force surrounding the armature and traversing the field magnet and.armature core members. I

While I have shown my invention in its simple and preferred form, it isnot so limited but is susceptible of various modifica-;

tions within the scope of theappended claims. r

I claim as my invention:

1. In adynamo-electric machine, the combination with a metallic end bellfor 5G tially closing one end of said machine, of an annular disk of1nsulating"mater-ial extending from said end bell to the shaft of saidmachine for completely inclosing the end of said machine.

2. Ina dynamo-electric machine, the combination with a metallic end bellfor par-,

tially closing one end of said machine, of an annular disk of insulatingmaterial extend Iing from said end bell to the shaft of said metallicring closely encircling the shaft of said machine, a plurality of radialsupports secured to said bell and said ring and insulated from saidring, and a plurality of seg ments of insulating material positionedbetween said supports and held in place thereby.

4. In a dynamo-electric machine, the combination with a metallic endbell for partially inclosing the ends of said machine, of

annular disks for completing the closure of the ends of said machine,each of said disks comprising a metallic ring closely surrounding theshaft of said machine, a plurality of radial supports rigidly connectedto said bell and said ring and insulated from one of said members, aplurality of notched segments of insulating material, and a plurality ofstrips adapted to be secured to said supports for holding said segmentsin place.

In testimony whereof, I have hereunto subscribed myjname this 24th dayof Feb.

RALPH E. GILMAN. Witnesses:

E. E. WISCHMEYER, B. B. HINES.

